docs: def dataframe(self):
          """
          Returns a pandas DataFrame containing all other class properties and
          values. The index for the DataFrame is the boxscore string.
          """
          if self._goals_scored is None and self._goals_allowed is None:
              return None
          fields_to_include = {
              'boxscore_index': self.boxscore_index,
              'date': self.date,
              'datetime': self.datetime,
              'game': self.game,
              'goals_allowed': self.goals_allowed,
              'goals_scored': self.goals_scored,
              'location': self.location,
              'opponent_abbr': self.opponent_abbr,
              'opponent_name': self.opponent_name,
              'overtime': self.overtime,
              'penalties_in_minutes': self.penalties_in_minutes,
              'power_play_goals': self.power_play_goals,
              'power_play_opportunities': self.power_play_opportunities,
              'result': self.result,
              'short_handed_goals': self.short_handed_goals,
              'shots_on_goal': self.shots_on_goal,
              'opp_shots_on_goal': self.opp_shots_on_goal,
              'opp_penalties_in_minutes': self.opp_penalties_in_minutes,
              'opp_power_play_goals': self.opp_power_play_goals,
              'opp_power_play_opportunities': self.opp_power_play_opportunities,
              'opp_short_handed_goals': self.opp_short_handed_goals,
              'corsi_for': self.corsi_for,
              'corsi_against': self.corsi_against,
              'corsi_for_percentage': self.corsi_for_percentage,
              'fenwick_for': self.fenwick_for,
              'fenwick_against': self.fenwick_against,
              'fenwick_for_percentage': self.fenwick_for_percentage,
              'faceoff_wins': self.faceoff_wins,
              'faceoff_losses': self.faceoff_losses,
              'faceoff_win_percentage': self.faceoff_win_percentage,
              'offensive_zone_start_percentage':
              self.offensive_zone_start_percentage,
              'pdo': self.pdo
          }
          return pd.DataFrame([fields_to_include], index=[self._boxscore])